基于车流冲突线的无信号交叉口风险分析

Model for Un-signalized Intersection Risk Evaluation Based on Traffic Conflict Line Theory

为更客观、系统地分析无信号交叉口的安全性能,提出“车流冲突线”概念.通过分析首部车冲突概率、碰撞后严重程度比和冲突向后传递长度,构建无信号交叉口安全风险评估模型.研究表明:基于临界冲突距离值构建的首部车冲突概率模型,考虑两车速度、角度、加速度和反应时间,更接近交通冲突的真实过程;借助物理碰撞学原理可确定3种冲突型态碰撞严重程度的权重关系,即,交叉∶合流∶分流为12.705∶1.000∶1.000;利用数学期望知识建立的交叉口当量期望车流冲突量模型,综合考虑冲突发生的潜在机率、交通量大小、车辆位置等因素,可更真实描述实际车流冲突行为.

In order to analyze the safety of un-signalized intersections more objectively and systematically,and make up for the deficiency of traditional research focuses on the conflict between two-vehicle,“traffic flow conflict line”was proposed.By analyzing the leading vehicle conflict potential probability,collision severities and transmission length of traffic conflicts,the safety risk assessment model of un-signalized intersections was constructed.The results show that the leading vehicle collision probability model based on the critical collision distance value,considering the speed,angle,acceleration and reaction time of two vehicles,is closer to the real process of traffic conflict.And three traffic conflicts weights were discussed when accident occurs(crossing conflict∶diverge conflict∶merge conflict is 12.705∶1.000∶1.000)according to the principle of physical collision.The model of equivalent expected vehicle-flow conflict at intersections based on mathematical expectation knowledge can describe the actual vehicle-flow conflict behavior more realistically by taking the potential probability,traffic volume,vehicle location and other factors into consideration.